body{
    margin:0;
    padding: 0;
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    background: #f5f5f7;
    background-size: cover;
}
.box
{
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%,-50%);
    width:400px;
    padding: 40px;
    background:rgba(255, 255, 255, 0.8);
    box-sizing:border-box;
    box-shadow:0 4px 12px rgba(0, 0, 0, 0.1);
    border-radius: 12px;/*登录窗口边角圆滑*/
}
.box h2
{
    margin:0 0 30px;
    padding:0;
    color:#333;
    text-align:center;
}
.box .inputBox
{
    position:relative;
}
.box .inputBox input
{
    width: 100%;
    padding: 10px 0;
    font-size: 16px;
    color: #333;
    letter-spacing: 1px;
    margin-bottom:30px;/*输入框设置*/
    border:none;
    border-bottom:1px solid #ccc;
    outline:none;
    background:transparent;
}
.box .inputBox label
{
    position: absolute;
    top: 0;
    left: 0;
    padding: 10px 0;
    font-size: 16px;
    color: #999;
    pointer-events: none;
    transition: .5s;
}
.box .inputBox input:focus ~ label,
.box .inputBox input:valid ~ label
{
    top: -18px;
    left: 0;
    color: #007aff;
    font-size: 12px;
}
.box  input[type="button"]
{
    background: #007aff;
    border: none;
    outline: none;
    color: #fff;
    padding: 10px 20px;
    cursor: pointer;
    border-radius: 5px;
    transition: background-color 0.3s;
}
.box input[type="button"]:hover {
    background-color: #005bb5;
}
